In commercial processes for reforming hydrocarbons with steam, reformer tubes are generally provided which are filled with a granular type of catalyst. The hydrocarbons, such as methane, natural gas, or a heavier feed stock is placed in contact with the catalyst together with a source of heat in order to provide synthesis gas. It has been the general practice to provide a catalyst in granular form which is disposed within the tubes, which are provided with a relatively small tube diameter for reasons of heat transfer and pressure. In these types of systems, it is necessary to expand a considerble amount of energy in order to pump the reacting gases through the granular catalyst bed. In order to overcome this problem attendant with prior steam reforming processes, in accordance with the present invention, a catalyst has been provided which is firmly adhered to a metallic strip that is removably positioned inside the tubes through which the process stream flows. It has been proposed to twist the metallic strip into a helical configuration, such that the relationship of the catalytic surface to the desired process stream velocity can be controlled by varying the helix of the metallic strip. Further, the degree of twisting or number of twists formed along the strip can be designed in accordance with the heat transfer relationship to the wall of the tubes. Also, by replacing the prior granular catalyst system with the twisted strip of the present invention, it is possible to significantly decreases the pressure drop throughout the system. The present limitation on minimum tube diameters which is dictated by the granular nature of the catalyst is no longer necessary when employing the present catalyst strip invention, thereby making it feasible to design steam reformers operating at higher pressures than heretofore has been possible. Thus, the present invention makes it feasible to reform feedstocks, with easier handling of the catalyst being possible.